Constraint Induced Movement Therapy for Post Stroke Paralysis
Constrained Induced Movement Therapy is a breakthrough approach that can train the brain to re-wire its neuronal connections and thus recover lost function due to the damage caused to the neurons in conditions such as Stroke. In a stroke, the brain neurons are damaged due to loss of blood flow and oxygen, as a consequence of the arterial occlusion (see image of the CT Scan of the Brain showing Stroke. Courtesy – Wikipedia.com)
Stroke patients are often left paralyzed (hemiplegia or hemiparesis) in their arms or legs (usually the side of the body opposite to the area of the brain damaged by the stroke, ). Until now most Post Stroke Functional Rehabilitation has been limited to physiological exercises in the effected limbs, with the hope that the brain can regain some of the lost functional capacity. Post stroke rehabilitation treatment is currently limited to providing some physiological exercises, usually in the form of supported hand or leg movements. This has shown to only have modest improvements and that too in some patients only.
Accumulating evidence on the use of Constraint Induced Movement Therapy is changing the way how such patients can regain movement of their paralyzed extremities and in some cases even their cognitive functions like the ability to speak.
For instance, according to the results of the Extremity Constraint Induced Therapy Evaluation (EXCITE) Clinical trial, published in JAMA (2006;296:2095-2104), CIMT is the first rehabilitation modality to show significant progress in helping patients regain motor functions (details below)
The central idea behind the CIMT is based on the pioneering work done by Edward Taube in 1977 when he was still a graduate student at Columbia University. Taube found that when the spinal connections from the arms or legs of monkeys was severed on one side, while simultaneously immobilizing the “good” arm or leg using straps, the monkeys were able to regain some movement in their limbs that had their neuronal connections severed! When the good side arm was not immobilized, the monkeys didn’t regain movement in the severed arm. Taube termed this phenomenon as “learned non use“, that once the brain realized that it could no longer command the arms and legs to move on the severed side, it “learnt” that this side could no longer be used and thus stopped “trying” to command the effected limb.
On the other hand, the brain seems to follow a “use or lose it” principle (see Norman Doidge’s excellent account in the ‘Brain that Changes Itself‘) – the good side’s neuronal connections expand into the non used parts of the brain that was earlier processing the signals from the effected limb, further reducing the chance for the brain to rewire and regain some movement.
CIMT is administered to patients by providing them a very focused and rigorous physical training regimen for two weeks. In this time period, their good limb is strapped and immobilized using a mitt for ninety percent of the time the person is awake. And the effected limb is made to do a series of movements, starting with assisted movements to more complex self initiated movements (see picture of patient undergoing CIMT)
The strapping of the good limb (note the white mitt in the picture above) is the key as it reduces the overwhelming inputs from this arm that inhibit any weak signals that may arise in the effected part of the brain from the effected limb. Given the impetus to move, perhaps as a survival mechanism, the brain then begins to fire up the neurons that control the movement of the effected limb. Given that only few neurons in the damaged part of the brain remain, the signals are at first weak. But with constant effort to move the effected limb, the brain gets a chance to rewires its network so that the weak signals can be picked up by the neurons which are controlling the good limbs. As the EXCITE trial showed, after just two weeks of therapy, the CIMT group (compared with controls) achieved a 34% reduction in time to complete a task and a 65% increase in the proportion of tasks performed spontaneously with the partially paralyzed arm. These improvements persisted even twelve months later.
Till date some 300 patients have benefited from CIMT. If you have stroke induced paralysis, i would highly recommend that you consider making a call to Dr. Taube’s clinic and research center